Exchange account added (with problems), mail syncs but doesn't send - says user is not authorized to send mail on behalf of this user

I’ve installed eM Client V6 on 9 Machines.

1st problem that occurs is that eM Client doesn’t find the client’s Exchange server. I enter the clients emails, password and it finds the exchange client of a neighbouring company on a different subnet. Given me that the credentials for the server are wrong and no way to change the server address.
But I’ve gotten past that. Told eM Client the email address is example@blabla.com and it told me it can’t find the server, then I manually told him where the server is - in this case, 192.168.2.3 - and it adds the mail and the mailbox fine. It downloads all the mails as well.

2nd problem encountered is that the account won’t send out any mails. The error is displayed as such:

9:49:04   MailExceptions.OperationException: Sending email failed with an error: The user account which was used to submit this request does not have the right to send mail on behalf of the specified sending account. —> Microsoft.Exchange.WebServices.Data.ServiceResponseException: The user account which was used to submit this request does not have the right to send mail on behalf of the specified sending account.

The exchange server also has DNS service on it and all the computers in the company are connected to the server and are in the local domain.
The user logging onto the computer is User1, but uses email address belonging to User2. In Exchange Maintenance Console, User1 has Full Access/Send As permissions for User2 - in Outlook, that’s enough to send mail as another user.
In eM Client however, that doesn’t appear to be enough.

The client receives the mails without a hitch, outgoing get stuck with that message.

I’ve turned on the logging for the EWS services and sent the logs to Paul McGregor on eM staff.

Solution?

P.S.: There seems to be numerous other topics open with the same problems described, but I’m creating a new one as per instruction by earlier mentioned customer support persona.

Best regards.
Aleš

Hi Ales, are you using Exchange 2007 on your mail server? This has proven to be a configuration issue caused by a specific set of updates on the Exchange 2007 server.

What version of eM Client are you currently using on your computer, can you please check the exact version number in Help > About?

Thank you.

Regards,
Paul

It’s a Microsoft Small Business Server with Exchange 2007.
The eM Client version is 6.0.21372.0

Hi again Ales, just to make sure, can you please navigate to Tools > Settings > Advanced and enable Exchange Web Services logging, 

  1. Save the settings
  2. Restart the application
  3. Replicate the issue
    Once the error reoccurs, please submit the logs using the “Send logs” button in the advanced settings window with a reference URL link to this forum topic.

However I’m afraid this is a server settings issue, rather than an application as has proven with other users receiving this error.

Thank you,
Paul

Before I do that. How are the logs going to be sent if the client doesn’t send any mails?

You can drag and drop the logs from the compose message with the logs attached, or you can find the logs in your logs folder under user/App Data/Roaming/eM Client/Logs to send the logs using the Outlook Web App.

Thank you,
Paul

The logs have been sent to support but no answer is forthcoming yet.

Any solution to my issue so far?

Hi Ales, sorry for the belated response, I’ve just submitted more information about the issue to you, please try to update your eM Client to the release received in my response and check if the issue persists.

Thank you,
Paul